I'm pretty sure they are usable on any modular PSU much like BitFenix alchemy cables. Just the Corsair ones aren't extensions
True, ive compared the psu ends of my antec true power 750 and my corsair hx850. The connector ends are keyed differently, and the internal metal pins are in different locations on the connectors.There is no standard for the psu end of modular cables, hence there being different kits for the corsair ranges. i.e the ax1200i kit does not work with the ax1200 and vice-versa.